lima: support exporting dma_buf
Created by: enunes
This enables lima to export a shared buffer from a dma_buf handle using the DRM prime infrastructure. With this, it is possible to export a gbm_bo allocated with lima to the display driver for rendering to a display.
This was tested on the Allwinner A20 with the sun4i-drm driver, along with lima.
Signed-off-by: Erico Nunes nunes.erico@gmail.com